1. Field of the Invention
The invention relates in general to a digital television broadcasting technique, and more particularly, to a technique for determining a symbol rate of a digital television signal.
2. Description of the Related Art
With advancements in communication techniques, digital television broadcasting gradually matures. Apart from being transmitted via cables, digital television signals can also be transmitted in wireless signals via a base station or a satellite. The Digital Video Broadcasting-Satellite (DVB-S) and the Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) are prevalent standards in digital television broadcasting.
The symbol rate is the number of symbol changes (waveform changes or signaling events) made to a transmission medium every second with a digitally modulated signal. In both DVB-S and DVB-S2 specifications, a symbol rate of digital television signals is an arbitrary value between 0 to 45 MHz, which means the symbol rate can be any value in a rather wide range. Since a receiver cannot be informed of a carrier channel and a symbol rate selected at the transmitter in advance, the receiver must scan all channels and the entire symbol rate range to correctly decode and restore a received signal. However, the sequential scanning toward all parameter combinations by the receiver is extremely time consuming, and such approach is far from an ideal solution from both efficiency and performance perspectives.